After the drive shaft broke, according to a Sugarloaf news release, the primary brakes — including the brake that prevented the lift from rolling in reverse — were left inoperable.

Sugarloaf said a “manufacturer design issue” in a lift component contributed to the rollback by compromising the lift’s ability to prevent it.

The component, a “drop dog” in ski parlance, is meant to automatically deploy to prevent lifts rolling back. Sugarloaf says an “inappropriate” safety switch in the drop dog allowed the rollback to occur.

Other Sugarloaf lifts were stopped until inspections of their equipment were completed and the components changed, according to the resort.

Saturday’s rollback was eventually stopped by an emergency brake, called a bullwheel brake. That brake worked, according to Sugarloaf, but is designed to bring the lift to a gentle stop.

Weighted full of more than 200 weekend skiers, Sugarloaf says the King Pine lift rolled back 460 feet before coming to a stop.